The present invention relates generally to an apparatus and method for transferring wafers, and more particularly to an industrial robot for transferring semiconductor wafers to and from a wafer cassette having a plurality of wafer receiving slots.
In the manufacture of integrated circuits and other computer components, semiconductor wafers are moved through many processing operations or steps, and wafer transfer robots are commonly used for this purpose. Typically, the semiconductor wafers are stored in wafer cassettes for convenience in handling the wafers in groups, and the wafer transfer robot transfers individual wafers to and from the wafer cassettes and to and from various processing operations. It is highly desirable that the wafer transfer robot be capable of handling the semiconductor wafers accurately, reliably and without damaging the surface of the wafer. Throughout the wafer handling process, the robot must maintain very high standards of cleanliness to avoid contamination of the wafer. It is also desirable that the wafer handling apparatus be capable of providing a relatively high wafer throughput while maintaining careful and precise handling of each individual wafer.